Structural Square Research Articles

Building size and disinfectant type influence the detection and concentration of Mycobacterium spp. in hot water plumbing

The number of nontuberculous mycobacteria (NTM) lung disease cases is increasing in the United States (US). This respiratory disease is primarily caused by three NTM species: Mycobacterium avium, M. intracellulare, and M. abscessus. Since disease transmission could occur through water aerosolization, this study investigated these three species' occurrence (sporadic and persistent) in hot water samples collected from residences (n = 70) and office buildings (n = 30) across the US. A longitudinal survey design was used. Three quantitative Polymerase Chain Reaction (qPCR) assays were used to measure the mycobacterial species in the water samples. Additionally, the water's disinfectant residual was measured. A structure's age and square footage were evaluated to predict mycobacterial contamination. Also, the seasonal occurrence of each species was assessed by structure type. Residences had a 43 % (30/70), and office buildings had a 77 % (23/30) detection frequency of one or more Mycobacterium spp. in their hot water. The age of the structure influenced M. intracellulare detection frequency but not M. avium and M. abscessus. The structure's square footage affected M. avium and M. intracellulare detection frequency but not M. abscessus. In chlorinated water, M. intracellulare was detected 1.4× more often in office buildings' hot water than in chloraminated water. In chloraminated water, the Mycobacterium spp. were detected 2–2.5× more often in residences, while M. avium and M. abscessus were detected 1.5–2.3× more often in office buildings, compared to chlorinated water. Each Mycobacterium spp. had a different trend associated with the type of structure and disinfectant. Further research is needed to better understand NTM occurrence in the built environment to improve public health.

Numerical study on the internal fluid mixing and its influencing mechanisms of the wave-driven floating photobioreactor for microalgae production

The wave-driven floating photobioreactors (PBRs) with advantages of easy in scaling-up, low energy inputs and low fabricating cost, hold great potential for massive and cost-energy effective microalgae production. However, their applications may be seriously challenged by intermittent waves that could produce very poor mixing under poor wave conditions, leading to a significant reduction of biomass productivity or even collapse of the cultures. To improve the utilization efficiency of waves for efficient and stable microalgae production in the floating PBRs, this work aims at numerically studying the fluid-dynamics of the floating PBRs, as well as the effects from wave conditions, culture depth and three different PBRs’ structures of square, rectangular and circular types. The results showed that the liquid inside the floating PBRs follow a periodic sinusoidal and reciprocating flow, and the square PBR had aggressive mixing characteristics at high wave excitation frequency, while the rectangular PBR produced more intense mixing at low wave excitation frequency. Regarding the culture depth, the dependence of liquid mixing on the culture depth showed a decreasing trend. Moreover, the results indicated that the PBRs with a high culture depth had several dead zones, although there was apparent upward flow at the high excitation frequency. This work provides valuable insight into increasing the utilization efficiency of wave energy for mixing enhancement in the floating PBRs and their design.

Džamije u Gornjem i Srednjem Polimlju podignute u vrijeme osmanske vlasti

Džamije u Gornjem i Srednjem Polimlju podignute u vrijeme osmanske vlasti

Chalcogenide Photonic Crystal: Channel Drop Filter

In the present paper, we have studied a two-dimensional photonic crystal structure of square lattice as channel drop filter application. Photonic crystal structure of square lattice was constructed with circular rods are embedded in air medium. The channel drop filter was designed with a point defect cavity nearby a waveguide, which constructed by removing a single row of rods near cavity. The cavity was designed by removing a number of rods, which characterized with dimension of the cavity. The transmission spectra were analyzed for the channel drop filter with the dimension of the cavity.

Comparative study on progressive collapse analysis of RC frame buildings subjected to wind and seismic loads

Progressive collapse occurs when the local failure of the primary structure leads to an eventual collapse of the structure as the adjoining load-bearing elements fail to transfer the load of the lost column. This analysis checks whether the load transfer from adjoining members upon loss of columns. A 10-storey RC structure of square and circular plan geometry were considered in this study. The buildings were modelled and designed for gravity, wind and earthquake loads as per the guidelines of respective Indian Standards. Further those models were examined for progressive collapse considering different critical column removal scenarios. The DCR results were calculated for the adjacent beams and adjacent columns to check whether the structure elements reach an alternate equilibrium of the load path or not. Out of both the geometry, the circular plan building was showing better performance then square plan building and it is about 10% to 20% better based upon all the analysis and for different loading conditions.

Research on the influence of different obstacle structures on the energy distribution characteristics of pulse detonation gas

In order to improve the gas energy conversion efficiency at the outlet of the pulse detonation combustor, numerical calculation methods were used to study the influence of three different cross-section obstacle structures of square, circle and trapezoid on the distribution characteristics of gas pressure potential energy, kinetic energy and internal energy in a single cycle at the outlet of pulse detonation combustor. The results show that: the expansion of pulse detonation gas mainly includes three-stages: primary expansion, secondary expansion, and over-expansion. Gas pressure potential energy, kinetic energy, and internal energy increase during the primary and secondary expansion stages, and decrease during the over-expansion stage. Pulse detonation combustor with trapezoidal cross-section obstacle structure has the smallest proportion of gas energy at the outlet of the combustor during the over-expansion stage and the highest proportion during the secondary expansion stage. Compared with square and circle cross-section obstacle structures, the gas energy distribution at the outlet of the pulse detonation combustor with trapezoidal cross-section obstacle structure is the easiest for turbomachinery to convert the gas energy.

Transportation Aspects of Shaping the Public Spaces of Urban Squares in Warsaw (Poland)

The aims of this paper are recognition of transport and urban characteristics of urban squares of the big European city on examples of Warsaw - capital of Poland, examine the relationship between the spatial and functional structure of urban squares and the solution of the road-street system and their transport service and presentation of transportation typology of urban squares. The analysis covered thirty selected Warsaw squares located in various parts of the city, mainly situated in the downtown and city center at left bank of Vistula River. The size of the square measured by the surface of the square, road-street layout of the square, public transportation service, with distinction of individual means of transport and exchangers, presence of pedestrian zones or green zones with pedestrian traffic in the area of the square and linear bicycle infrastructure serving the square and the Public Bike System station as well as possibility of parking solutions were analyzed. The results of the presented in this paper confirm that the analyzed squares are a very important element of creating the functional and spatial structure of the city of Warsaw. The tested squares are characterized by a very large diversity: in terms of surface area, solutions of the street system shaping the spatial structure of the square, the functions and categories of administrative streets crossing the square, traffic density volume, forms of transportation service by public transport and bicycle. Five types of squares were distinguished in terms of transport: pedestrian square, autonomous square, city local traffic square (urban square with local traffic), urban transit square of 1st and 2nd category. Pedestrian zones and green zones with dominant pedestrian traffic are an important element of shaping the space of squares and significantly affect the function of a given square. The analyzes show that, especially in the downtown and center, there are relatively few parking spaces located in Warsaw’s squares, and their number is decreasing. This is the result of the actions of city authorities promoting sustainable development policy, including travels to the city center and to downtown by public transport and bicycles. With a view to improving the attractiveness of public spaces in Warsaw squares, attention should be paid to the aesthetics and technical, functional and material standards of the transport infrastructure being implemented, as well as to improve the accessibility of public transport stops, ensure the consistency of the squares’ spaces with the bikeway system in the city.

2D selenium allotropes from first principles and swarm intelligence

Combining the particle-swarm optimization method with first-principles calculations, we explore a new category of two-dimensional (2D) monolayers composed of solely the element selenium. Three stable structures are screened from outputs of crystal search computations, namely T-Se (1T-MoS2-like), C-Se (tiled 1D helical chain), and S-Se (square structure). Phonon calculations, as well as formation energy calculations have been performed to confirm the stability of the three phases. The electronic structure calculations show that both T-Se and C-Se are indirect-band-gap semiconductors, with gap values of 1.11 eV and 2.64 eV respectively when using the hybrid HSE06 functional. In particular, C-Se has a centrosymmetry-breaking structure which provides a spontaneous in-plane ferroelectric polarization of about 2.68 × 10−10 C m−1 per layer. Interestingly, S-Se has a Dirac cone that can open up a band gap of 0.11 eV if spin–orbit coupling is included. The tilted Dirac cone of S-Se shows anisotropic band dispersion as characterized with different Fermi velocities of 1.26 × 106 and 0.24 × 106 m s−1 around the Dirac point. Our works enrich the family of 2D materials of selenium allotropes and show that their versatile properties could give rise to potential application in various fields.

사각 습식 스크러버 내부구조에 따른 유동특성

사각 습식 스크러버 내부구조에 따른 유동특성

Construction Risk Assessment through Partial Least Square Technique

Construction industry in developing and under developing country has the priority among the other industries. It assumes safe investment in an uncertain market on behalf of privatization. It is most important that the project in this industry is managed as per the best project management planning practice. In the developing country the project manager faces a lot of difficulties to manage the project. There are various factors which are responsible for the project progress and controlling. In this research we incorporate some factors which influence the project progress among all other factors. The main motive of this research is to analyze the factors which are responsible for the progress of the project. From literature survey and expert opinion we consider seven main factors and their 31 sub factors which are analyzed by “PARTIAL LEAST SQUARE STRUCTURE EQUATION MODELING” based on SMART PLS3.0 software. It finally determines which factor in construction project play a major role in the whole risk of that project.

Topologically Protected Photonic Edge States in the Visible in Plasmo‐Gyroelectric Metamaterials

AbstractGyroelectric materials can be used to realize nontrivial photonic topological states. The usual strategy to maximize this effect is to increase the strength of the typically very small, off‐diagonal dielectric permittivity tensor components. This is a very difficult task, in particular at high frequencies. Here, an alternative method is proposed: reducing the strength of the diagonal permittivity tensor components. It is shown that this can be achieved by employing a layered plasmo‐gyroelectric metamaterial as the background medium of a 2D photonic crystal. It is demonstrated that by applying magnetic field, which breaks time reversal invariance, a topologically nontrivial photonic gap opens in the band structure of square and hexagonal photonic crystals. This is confirmed by detecting the presence of a topologically protected edge state at the boundary of this structure. This state is a photonic analog of the edge state in the conventional integer quantum Hall effect, also characterized by suppressed backscattering.

On quantitative expression in fibrous composites based on an exemplary distribution of roving glass-fibers

Abstract The paper deals with analysis of relationships between the microgeometry and mechanical properties of fiberglass i.e. epoxy resin composites with random fibers distribution. The mechanical properties (e.g. a flexural modulus E f , taking into account shear effects) of the material were determined in bending by Short Beam Shear Tests (SBST). Microgeometry of the structure was characterized on the basis of microscopic images of test specimens. The paper proposes a new measure of irregular reinforcement distribution expressed as an area ratio of the matrix surrounding the single fiber to the circuit of the fiber. The measure, denoted by G AB , is expressed in microns. In particular the relationship between the results obtained in the test samples with random distribution of fibers and theoretical regular structures of square (K) and hexagonal (H) type is presented. Specimens of the investigated composite (E-glass fibers and Epidian 5 epoxy resin), supplied by industrial partner, were cut out from raw material of helicopter blades girders. The obtained experimental results for the analyzed composite corresponded to approximation by the theoretical model of the square (K) type. The results can be used to estimate the flexural elastic modulus E f of the unidirectional composites with irregular arrangement of fibers, made manually or using the molding apparatus. Based on those results, it can be concluded that the square distribution model (K) is appropriate for numerical estimation of the strength composites properties reinforced with glass fibers of circular cross-section, having the diameter in the range of 10–16 μm.

Basic structure of square and circle for defected waveguide structure

Many existing waveguide designs focus on the application such as antenna and filter. Besides that, metamaterial used to design with waveguide is usually conducted by loading method. The configuration such as the walls or planes of waveguide is rarely proposed and designed. The motivation of this paper is to introduce the Defected Waveguide Structure (DWS) in waveguide to operate in Ultrawideband (UWB) frequency range. DWS is designed by using basic structure of square and circle. The square and circle are designed at all the walls of waveguide in patch. Hybrid design by mixing the square and circle is also proposed. The performance of DWS towards waveguide is analysed by using the transmission coefficient (S21) and reflection coefficient (S11). The filter circuit is constructed for modelling purpose to determine the value of inductance and capacitance. Copper waveguide acts as high pass filter at the frequency larger than cut off frequency 2.76GHz. The square DWS design works as band pass filter with narrowest bandwidth of 5.19GHz. The circle DWS design achieves the widest bandwidth of 6.55GHz for the pass band performance. Hybrid design improves the bandwidth slightly compare to square DWS design by 0.54GHz.

Structure of squares and efficient domination in graph classes

For any two vertices u and v in a graph G, dG(u,v) denote the distance between u and v in G. The square of a graph G=(V,E) is the graph G2=(V,E2) such that uv∈E2 if and only if dG(u,v)∈{1,2}. An efficient dominating set (e.d. for short) in G is a subset D of vertices such that D is an independent set and each vertex outside D has exactly one neighbor in D. In general, (i) if P is a (hereditary) graph property, and if a graph G satisfies P, then G2 does not need to satisfy P, and (ii) if H is any graph, and if G is a H-free graph that has an e.d., then G2 need not be H-free.In this paper, we show that the squares of (P6, banner)-free graphs that have an e.d. are again (P6, banner)-free. This result together with some known results implies that the Efficient Dominating Set problem (which asks for the existence of an e.d. in a given graph G) can be solved in time O(n3) for (P6, banner)-free graphs. Here, Pt denotes the chordless path on t vertices, and a banner is the graph obtained from a chordless cycle on four vertices by adding a vertex that has exactly one neighbor on the cycle.

Contact-Free Templating of 3-D Colloidal Structures Using Spatially Nonuniform AC Electric Fields.

The formation of ordered and regularly shaped structures of colloidal particles with the aid of spatially nonuniform electric fields is a modern research area of great interest. This work illustrates how alternating current (AC) electrokinetic effects (dielectrophoresis, electroosmosis) can serve as contact-free templates, inside which colloidal microspheres can assemble into a variety of shapes and sizes. We show how three-dimensional colloidal structures of square, circular, and diamond shape of many tens of micrometers in size can be reproducibly formed with a single set of quadrupolar microelectrodes. Numerical simulations performed help to explain the role of AC electroosmosis and AC dielectrophoresis on the shaping of these structures as a function of applied voltage and frequency. We also demonstrate how the templating repertoire is further enhanced with the simultaneous application of a second, individually controlled AC electric field, which enables a variety of asymmetric colloidal structures to be produced using the same set of quadrupolar microelectrodes. As the preservation of shape and size of such electric-field templated structures after medium evaporation still remains a big challenge, here we also report on a novel method that permits the stabilization and isolation of these particle assemblies through medium gelation and subsequent hydrogel removal with a UV/ozone treatment.

Methodology and Design of a Massively Parallel Memristive Stateful IMPLY Logic-Based Reconfigurable Architecture

Continued dimensional scaling of CMOS processes is approaching fundamental limits and, therefore, alternate new devices and microarchitectures are explored to address the growing need of area scaling and performance gain. New nanotechnologies, such as memristors, emerge. Memristors can be used to perform stateful logic with nanowire crossbars, which allows for implementation of very large binary networks. This paper involves the design of a memristor-based massively parallel datapath for various applications, specifically single instruction multiple data and parallel pipelines. The innovation of our approach is that the datapath design is based on space-time diagrams that use stateful IMPLY gates built from binary memristors. The paper also develops a new model and methodology to design massively parallel memristor-CMOS hybrid datapath architectures at a system level. This methodology is based on an innovative concept of two interacting subsystems: 1) a controller composed of a memristive RAM, MsRAM, to act as a pulse generator, along with a finite-state machine realized in CMOS, a CMOS counter, CMOS multiplexers, and CMOS decoders; 2) massively parallel pipelined datapath realized with a new variant of a CMOL-like nanowire crossbar array, memristive stateful CMOL with binary stateful memristor-based IMPLY gates. In contrast to previous memristor-based FPGA, our proposed memristive stateful logic field programmable gate array uses memristors for both memory and combinational logic implementation. With a regular structure of square abutting blocks of memristive nanowire crossbars and their short connections, our architecture is highly reconfigurable. We present the design of a pipelined Euclidean distance processor along with its various applications. Euclidean distance calculation is widely used by many neural network and similar algorithms.

Performance Analysis of 2D-Ebg under Monopole Antenna

The artificial properties in two dimensional electromagnetic structures (2D-EBGs), such as PMC and Band Reject Region are investigated for a proposed structure of square shaped mushroom. The radiation characteristics of monopole antenna over this 2D-EBG is tested by considering two cases. During first case monopole antenna is made to operate within band rejection region. Second case monopole antenna made operate outside the band rejection range. The obtained results during first case is showing enhancement in operating band width and smoother radiation pattern. In second case the effect is null and 2D-EBG resembles like conventional plane reflector. The simulated results are presented.

Kekulé structures of square–hexagonal chains and the Hosoya index of caterpillar trees

Let Rn be a square–hexagonal chain. In this paper, we show that there exists a caterpillar tree Tn such that the number of Kekulé structures of Rn is equal to the Hosoya index of Tn. Since both hexagonal chains and polyomino chains can be viewed as special square–hexagonal chains, our result generalizes the corresponding results for hexagonal chains (Gutman, 1977) and polyomino chains (Liand Yan, 2012).

Efficient synthesis, structure, and complexation studies of electron-donating thiacalix[n]dithienothiophene.

A series of thiacalix[n]dithiothiophenes (n=4-10) was prepared by a facile method and X-ray analysis was used to determine the molecular structures of square- (4-mer) and pentagonal-shaped macrocycles (5-mer). In the cyclic voltammograms, reversible multielectron redox processes, which are due to electronic delocalization, were observed at low oxidation potentials. The cyclic 4-mer acted as a "Janus-head" cavitand for two C60 molecules, whereas the 5- and 6-mer formed stable 1:1 complexes with C60 .

Efficient Synthesis, Structure, and Complexation Studies of Electron‐Donating Thiacalix[n]dithienothiophene

AbstractA series of thiacalix[n]dithiothiophenes (n=4–10) was prepared by a facile method and X‐ray analysis was used to determine the molecular structures of square‐ (4‐mer) and pentagonal‐shaped macrocycles (5‐mer). In the cyclic voltammograms, reversible multielectron redox processes, which are due to electronic delocalization, were observed at low oxidation potentials. The cyclic 4‐mer acted as a “Janus‐head” cavitand for two C60 molecules, whereas the 5‐ and 6‐mer formed stable 1:1 complexes with C60 .